This invention relates generally to machines for severing standing crops from the ground using a cutterbar having a plurality of rotatable discs having knives mounted thereon to sever standing crop by an impact action upon rotation of the discs and, more particularly, to an improved rock guard for the rotatable discs that streamlines removal and replacement of knives on the cutterbar.
Rotary disc cutterbars are well known in the agricultural arts and used in the harvest of a variety of standing crops. A typical disc cutterbar comprises a plurality of cutterheads spaced along the length of the cutterbar. The cutterheads each typically comprise a rotating cutting disc including diametrically opposed cutting blades (though configurations with three or more blades are known) driven by a drivetrain housed within the cutterbar that receives motive power from the prime mover to which the disc mower is attached. The knife alignment on adjacent cutterheads is typically rotated 90 degrees to provide for cutting overlap without the risk of knives on adjacent cutterheads coming into contact. For background information on the structure and operation of some typical disc cutterbars, reference is made to U.S. Pat. No. 5,996,323, issued to Campbell, the descriptive portions thereof being incorporated herein in full by reference.
Cutterbars frequently impact rocks and other obstructions in a field which can damage the knives. Further, knives also become dulled by their interaction with the crop and require periodic removal for sharpening or replacement. This has led to the development of various quick-change knife systems which reduce the time necessary to change the knives on a cutterbar.
Rock guards are provided on the underside of rotary cutterheads to protect the rotating cutterheads and knives from impact with rocks and other obstructions as the cutterbar is moved across the ground. With the emergence of quick-change knives, rock guards have been modified to permit knife removal without requiring removal of the rock guards, typically by incorporating a single recessed area forwardly disposed in the rock guard which permits blade removal. The configuration of most rotary cutterbars requires that the rotary cutters be realigned, typically four times in order to replace all of the knives on the cutterbar.
It would be advantageous to provide an improved rock guard for use on rotary cutterbars with quick-change knives that would reduce the number of rotary cutter realignments necessary for a complete knife change on the cutterbar. Additional advantages would be realized by an improved rock guard that retained the same basic design as current rock guards allowing easy retrofit on existing cutterbars. Still further advantages would be realized by an improved rock guard for a rotary cutterbar having a quick-change knife attachment system that permits the same tool-free knife changes while maintaining a full cross-section on the leading edge of the rock guard to maximize the wear surface.